Almost exclusively, wheeled land vehicles (typically, forklifts, some small front bucket dumpers used in construction, and other specialized steering devices excepted) employs direct front wheel steering as a directional steering means. The greater the wheelbase, the greater tendency of the rear wheel(s) to ‘straight line’ the front wheels and clip corners.
Innovations in the automotive industry have mitigated this shortcoming with the introduction of front and rear wheel steering, with the vehicle chassis remaining a rigid structure.
Human (pedal) powered cycles (particularly bicycles and tricycles) have been used as a mode of transport for over a century throughout the world. Most bicycles and tricycles are characterized by a frame which is coupled to two or three wheels, a seat, handlebars and a crank.
Typically the frame includes a fork to which a front wheel is rotatably coupled at one end and handlebars attached at the opposite end. The cranks may be either directly coupled to the front wheel or alternatively coupled via a chain to a rear wheel. The seat is supported on the frame so that a rider is ergonomically placed to deliver maximum power in a comfortable position, relative to the components and weight distribution.
Several decades ago, recumbent cycles became available to the general public. Most, but not all recumbent cycles comprise three wheels and are characterized by a relative juxtaposition of seat, cranks and handlebars such that the rider is in a reclined or recumbent position when riding the cycle.
Recumbent cycles are sometimes shunned for different reasons including perceptions that they were simply a fancy type of tricycle and lack the handling characteristics of a bicycle.
One such cycle is discussed in U.S. Pat. No. 6,062,581 which discloses a front wheel pedal bicycle with handlebars arranged under the seat on a vertical pivot axis. The handlebars swing forwards and backwards at each end thereof in order to steer the front wheel via twin cables connected between the handlebar and the steering column. The front to back swinging handlebars due to the vertical pivot axis conflicts with the rider's legs pedalling the front wheel. The handlebars do not articulate with the front sub-frame, thereby causing an uncomfortable rider experience due to only the front wheel frame lean steering.
U.S. Pat. No. 4,789,173 discloses a three wheel recumbent cycle with a front frame pivoted to a rear frame supported on two rear wheels. The seat is attached to the upper frame which pivots to lean steer the tricycle. Handlebars are positioned under the seat but are rigidly fixed under the seat to the frame supported by the rear wheels. Only lean steer is used to steer the vehicle. There is no handlebar steering.
U.S. Pat. No. 5,240,267 discloses a lean steer cycle having a pair of rear wheels which remain in normal upright contact with the road surface whilst the front single wheel is steered by lean steering the entire front frame with seat and handlebars in one unit.
Other arrangements exist, such as in U.S. Pat. No. 5,568,935 which discloses a tricycle type recumbent cycle a pair of rear wheels is supported on a rear axle, with propulsion by pedals to the front wheel. The front frame and seat tilt by lean steering which causes the front wheel to turn. No handle steering is provided.
Another arrangement is disclosed in U.S. Pat. No. 4,572,535 that teaches an alternative arrangement of recumbent tricycle with lean steering and fixed handlebars.
Direct drive cycles (where a rider pedals an axle of a wheel that is also being steered) suffer from pedal force/torque feedback. A rider's pedalling generates alternating steering torque which when fed back to the handlebars needs to be resisted by the rider. In resisting this feedback the rider can induce a wobble through the handlebars. A reduction in this feedback would provide a cycle design that is more comfortable for the rider by reducing the rider's tendency to induce wobble through the handlebars and thereby assist in keeping the cycle on a straight line.
In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word ‘comprise’ or variations such as ‘comprises’ or ‘comprising’ is used-in an inclusive sense; i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.
With the aforementioned in view, it is an object of the present invention to provide alternative form of a cycle steering which attempts to redress one or more of the above mentioned problems.
It is desired to provide improved cycle steering for improved high and low speed manoeuvrability of the cycle.
It would further be desirable to provide an upright easily visible seating position, a construction of reduced complexity compared to other tilting cycles, suppression of pedal feedback to the handlebars and a lightweight design for a tilting cycle.